1. Field of the Invention
This invention relates to haptic interfaces and, in particular, to varying the resolution of the haptic display of a haptic interface device.
2. Related Art
A xe2x80x9chaptic interface devicexe2x80x9d provides a haptic sensation (haptic display) to a user of the haptic interface device in response to the user""s interaction with an environment with which the haptic interface device is associated. xe2x80x9cHapticxe2x80x9d refers to the sense of touch: haptic interface display devices thus produce sensations associated with the sense of touch, such as texture, force (e.g., frictional force, magnetic repulsion or attraction), vibration, mass, density, viscosity, temperature, moisture, or some combination of such sensations. Haptic interface devices can be embodied in a variety of different apparatus, such as, for example, apparatus for conveying force and/or vibrotactile sensation (e.g., a stylus, a movable arm, a wheel, a dial, a roller, a slider or a vibratory surface), apparatus for conveying thermal sensation (e.g., a thermally-controlled surface or air volume), and apparatus for conveying the sensation of moisture (e.g., a moisture-controlled surface or air volume). Haptic interface devices can be used in a wide variety of applications. For example, some joysticks and mice used with computers incorporate force feedback to provide a haptic display to a user of the joystick or mouse. Some paging devices are adapted to vibrate when a paging signal is received. Some toys produce vibrations as part of the interaction with the toy. These examples give an indication of the range of applications for which a haptic interface device can be used.
In a conventional haptic interface device, the character of the haptic display experienced by a user is determined by a haptic model that links the state of one or more aspects of the environment to the haptic sensation provided to the user. This is illustrated in FIG. 1. A user 101 uses an environment interaction control apparatus 103 to interact with an environment 102 via an environment interaction model 104 (either directly or via a haptic model 106, as indicated in FIG. 1 by the dashed lines between the environment interaction model 104 and the environment 102, and the environment interaction model 104 and the haptic model 106). The haptic model 106 xe2x80x9cinterpretsxe2x80x9d the user interaction with the environment 102 (based on information concerning the user interaction obtained either from the environment interaction model 104 or the environment 102, as indicated in FIG. 1 by the dashed line between the environment interaction model 104 and the haptic model 106 and the dashed arrow head entering the haptic model 106 from the environment 102) to cause a haptic display apparatus 105 to produce a corresponding haptic display. The environment interaction model 104 can also cause a non-haptic display apparatus 107 to produce a non-haptic display (e.g., a visual display and/or an audio display). However, there need not necessarily be a non-haptic display (as indicated by the dashed lines between the non-haptic display apparatus 107 and the environment interaction model 104 and user 101).
The magnitude of the change in haptic sensation per unit change in the state of one or more aspects of the environment is referred to herein as the xe2x80x9cresolutionxe2x80x9d of the haptic display. For example, in a haptic interface device used for video browsing and/or editing, a knob can be rotated to advance through the frames of a video recording, a force being applied in opposition to rotation of the knob, to simulate a detent, at predetermined transitions from one video frame to the next in the video recording. The resolution of the haptic display in that haptic interface device can be the frequency of occurrence of detents in the video recording (e.g., the number of video frames between each detent). (It can also be possible, as illustrated by an example discussed further below, to define the resolution of the haptic display of such a haptic interface device in terms of the frequency of detents per unit duration of time over which the video was obtained.)
In previous haptic interface devices, the resolution of the haptic display cannot be changed by a user of the haptic interface device. (As explained further below, a xe2x80x9ccreatorxe2x80x9d of the haptic interface device may change the resolution of the haptic display.) In particular, a user of a haptic interface device has not been able to change the resolution of the haptic display during use of the haptic interface device. For example, in the above-described haptic interface device used for video browsing and/or editing, the resolution of the haptic display remains constant during use of the haptic interface device by a user: a given amount of rotation of the knob always advances the video recording through the same number of video frames and passes through the same number of detents.
Herein, a xe2x80x9cuserxe2x80x9d of a haptic interface device is a person who engages in use of the haptic interface device for the intended purpose of the haptic interface device. A xe2x80x9ccreatorxe2x80x9d of a haptic interface device is a person who constructs some part or all of a haptic interface device (i.e., one or more of the models and/or apparatus of the haptic interface device as shown in FIG. 1) and thereby establishes the characteristics (e.g., haptic display resolution) of the haptic interface device. Thus, as used herein, a xe2x80x9ccreatorxe2x80x9d of a haptic interface device is not a xe2x80x9cuserxe2x80x9d of the haptic interface device, though the same person can act, at different times, in both capacities. As indicated above, a creator of a haptic interface device can change the resolution of the haptic display of a haptic interface device. This can be done by appropriately modifying one or more of the models and/or apparatus of the haptic interface device to produce a desired haptic display resolution. For example, a video browsing and/or editing haptic interface device as described above has been implemented so that the number of detents per complete revolution of the knob is established, prior to use of the haptic interface device by a user, based upon the nature of the video recording (e.g., 30 detents per revolution for a video recording acquired at 30 frames per second and 24 detents per revolution for a video recording acquired at 24 frames per second). (Such a haptic interface device is an example of a haptic interface device for which the resolution of the haptic display is defined in terms of the frequency of detents per unit duration of time over which the video was obtained, as opposed to frequency of detents per video frames of the recording.)
Current haptic interface devices do not enable a user of the haptic interface device to change the resolution of the haptic display and, in particular, do not enable the user to change the resolution of the haptic display during interaction with the environment. Further, a user of a haptic interface device has not been able to change the resolution of the haptic display using an apparatus through which some or all of the haptic display is provided to the user. Additionally, current haptic interface devices do not enable continuous change in the resolution of the haptic display. Thus, the user""s flexibility in interacting with the environment is inhibited when using a current haptic interface device.
A haptic interface device produces a haptic display in response to a user""s interaction with an environment with which the haptic interface device is associated. According to the invention, the resolution of the haptic display produced by the haptic interface device can be changed by the user. In particular, the invention can be implemented so that the haptic display resolution can be changed as the user interacts with the environment using the haptic interface device. Thus, the invention can enable a user to interact with a particular environment at different levels of detail (i.e., different resolutions) and, in particular, can enable the user to immediately change from interacting with the environment at one level of detail to interacting with the environment at a different level of detail. For example, the user can switch back and forth between interacting with the environment at a relatively coarse level of detail that gives an overall sense of the environment and interacting with the environment at a relatively fine level of detail that enables the user to obtain a more precise sense of a particular aspect of the environment.
The invention can also enable a user to change the resolution of the haptic display of a haptic interface device by interacting with haptic display apparatus (i.e., apparatus that provides some or all of the haptic display to the user) and/or environment control apparatus (i.e., apparatus used by the user to interact with the environment) of the haptic interface device. This capability greatly facilitates the ability of the user to change the resolution of the haptic display while simultaneously interacting with the environment. In particular, such capability enables the user to change quickly between different levels of haptic display detail.
The invention can also enable a user to effect continuous change in the resolution of the haptic display of a haptic interface device. The ability to continuously change the resolution of the haptic display enables the user to interact with the environment at any desired level of haptic display detail.
The invention can enable each of the haptic display, the user interaction with the environment, and the resolution control to be effected with one or more degrees of freedom. Further, the invention can enable each of the haptic display, the user interaction with the environment, and the resolution control to be effected by a translational or rotational input or output (as appropriate). (Other types of input or output can also be used if appropriate or desired.)